If the thing pledged is an obligation of a third person, the pledgee is entitled to enforce performance of the third person's obligation when it becomes due and to retain as security any payment or other thing received from the third person. The pledgee may apply any money collected to the secured obligation, even if not yet due. He must account to the pledgor for any payment or other thing remaining after the secured obligation has been satisfied.
La. C.C. § 3160